VXLAN based multicasting systems having improved load distribution

ABSTRACT

A virtual extensible local area network (“VXLAN”) system includes servers having VXLAN tunnel end points (“VTEP”) and virtual machines (“VMs”), multiple routers to transmit network data using bidirectional groups (“BIDIRs”) and rendezvous points (“RPs”), and an associated management and provisioning entity (“MPE”) adapted to arrange BIDIRs dynamically based upon network traffic such that traffic is more evenly distributed across the VXLAN. Some of the routers can be preconfigured as potential RPs, and the MPE can activate and deactivate these routers to and from RP status as needed. The MPE creates and rearranges BIDIRs based upon volume thresholds of traffic being reached in BIDIRs, such as by splitting overloaded BIDIRs. Network traffic can be monitored by VTEPs and RPs.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/907,762 filed on May 31, 2013, the full disclosure of which isincorporated by reference herein in its entirety and for all purposes.

TECHNICAL FIELD

The present invention relates generally to data communication networks,and more particularly to data communication networks that involvemulticast streams on virtual networks or portions thereof.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information, and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Advances in server virtualization have placed increased demands onphysical network infrastructures. For example, there can be a need formore Media Access Control (“MAC”) address table entries throughout aswitched network due to the potential attachment of hundreds uponthousands of Virtual Machines (“VMs”), each having its own separate MACaddress. Also, VMs may be grouped according to their Virtual Local AreaNetwork (“VLAN”), where thousands of VLANs might be needed in a givendata center in order to partition traffic properly. The current VLANlimit of 4094 can be inadequate in some situations. In response to theseand other problems that arise through continuing server virtualization,protocols and framework for a virtual extensible local area network(“VXLAN”) have been proposed.

In general, a VXLAN is a protocol for running an overlay network on anexisting infrastructure for Layer 3 (“L3”) (i.e., a network layer), suchthat a virtual network is built to support elastic computearchitectures. In essence, a VXLAN can connect multiple L3 networks andmake them appear to share the same Layer 2 (“L2”) domain. This allowsVMs to reside in different networks and yet still operate as if theybelong to the same L2. This is generally accomplished through the use ofparticular VXLAN-based network structuring, identifying, addressing andencapsulating, among other modifications to traditional VLAN systems. Ineffect, VXLAN can be considered a tunneling scheme with VM hosts (e.g.,ESX hosts) or “hypervisors” that are VXLAN Tunnel End Points (“VTEPs”).Other details of VXLAN can be found at, for example, the Internetwebsitehttp://datatracker.ietf.org/doc/draft-mahalingam-dutt-dcops-vxlan/,which is incorporated by reference herein for this purpose.

The introduction of such VXLAN solutions to the various foregoingproblems, however, can result in further issues with respect to such newsolutions and protocols. One problem can involve issues that arise whenseparate multicast trees are provided for one, more, or all tenants on aVXLAN. Another problem can involve issues that arise when separatemulticast trees are provided for each multicast stream within a giventenant. In these and other instances, an excessive concentration oftraffic on relatively few links across the VXLAN can present a realproblem in operating the VXLAN effectively.

Although many systems and methods for providing server virtualizationhave generally worked well in the past, there is always a desire forimprovement. In particular, what is desired are systems and methods thatare able to take the tendency of network traffic to concentrate on onlya few network links and distribute the overall load of trafficeffectively across an entire VXLAN topology instead.

SUMMARY

It can be an advantage of the present invention to provide improvedinformation handling systems and methods that utilize VXLAN environmentsto multicast effectively by distributing traffic loads more evenlyacross the network. This can be accomplished by preconfiguring numerouspotential Rendezvous Points (“RPs”) across the network topology,monitoring network traffic at active RPs, and rearranging or creatingnew bidirectional groups (“BIDIRs”) or trees in response to trafficthresholds being reached at any given RP.

In various embodiments of the present invention, a VXLAN system caninclude a plurality of servers, each having a VXLAN tunnel end point(“VTEP”) and a plurality of VMs thereupon. The VXLAN system can includevarious routers and/or switches coupled to the servers, with each suchrouter or switch being adapted to facilitate the transmittal of networkdata between the plurality of servers therethrough according todesignated BIDIRs having designated VMs thereupon. Multiple of saidplurality of routers can be preconfigured as potential RPs for BIDIRs.The VXLAN system can also include a processor coupled to the pluralityof routers, the processor having a management and provisioning entity(“MPE”) located thereupon. The MPE can be adapted to arrange BIDIRsdynamically based upon traffic passing through the plurality of routerssuch that traffic is more evenly distributed across the VXLAN.

In various detailed embodiments, the MPE is adapted to facilitate therearrangement of an existing BIDIR, such as based upon a volumethreshold of traffic being reached in the BIDIR. The MPE can be adaptedto facilitate the rearrangement of the existing BIDIR by creating a newBIDIR and facilitating moving one or more of the designated VMs from theexisting BIDIR to the new BIDIR. This can involve moving designated VMsby causing affected VTEPs to send Internet Group Management Protocol(“IGMP”) join requests to the new BIDIR and IGMP leave requests to theexisting BIDIR. In some embodiments, the RPs are adapted to monitortraffic passing therethrough. Also, the RPs can be adapted to sendnotices to the MPE when a volume threshold of traffic is reached. One ormore of the routers that are preconfigured as potential RPs may not actas RPs unless the MPE has designated them as an RP. Also, trafficpassing through the plurality of routers can be multicasting traffic.

In various further embodiments, a computing system adapted to manage aVXLAN can include a processor adapted to couple to and manage aplurality of VXLAN routers, servers, BIDIRs, VMs, RPs, VTEPs and thelike, as well as one or more software modules adapted to be executedwith respect to the processor. The module(s) can contain computer codefor an MPE that is adapted to arrange BIDIRs dynamically based upontraffic passing through the routers such that traffic is more evenlydistributed across the VXLAN. Again, the MPE can be adapted tofacilitate the rearrangement of an existing BIDIR based upon a volumethreshold of traffic being reached in the BIDIR. Other details of theprocessor and MPE can be similar to those for the full system embodimentabove.

In still further embodiments, various methods of distributingmulticasting load across a VXLAN can be provided. Such methods caninclude the process steps of preconfiguring a plurality of VXLAN routersas potential RPs, establishing one or more BIDIRs having designated VMsand activated RPs thereupon, monitoring network traffic at the activatedRPs, determining that a traffic threshold has been reached at anactivated RP within a given BIDIR, and removing one or more tenants fromthe given BIDIR and placing said one or more tenants into a differentBIDIR. In some embodiments, the different BIDIR can be a newlyestablished BIDIR in response to the determination that a trafficthreshold has been reached. In addition, the activated RP can send amessage to a management and provisioning entity (“MPE”) that the trafficthreshold has been reached.

Other apparatuses, methods, features and advantages of the inventionwill be or will become apparent to one with skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The included drawings are for illustrative purposes and serve only toprovide examples of possible structures and arrangements for thedisclosed inventive multicasting, load considering, and VXLAN-based datanetwork devices, systems and methods. These drawings in no way limit anychanges in form and detail that may be made to the invention by oneskilled in the art without departing from the spirit and scope of theinvention.

FIG. 1 illustrates in block diagram format the layout of an exemplaryVXLAN system according to one embodiment of the present invention.

FIG. 2A illustrates in block diagram format the layout of anotherexemplary VXLAN topology according to one embodiment of the presentinvention.

FIG. 2B illustrates in block diagram format an exemplary Management andProvisioning Entity (“MPE”) according to one embodiment of the presentinvention.

FIG. 3 provides a flowchart of an exemplary method of distributingmulticast load across a VXLAN according to one embodiment of the presentinvention.

DETAILED DESCRIPTION

Exemplary applications of apparatuses and methods according to thepresent invention are described in this section. These examples arebeing provided solely to add context and aid in the understanding of theinvention. It will thus be apparent to one skilled in the art that thepresent invention may be practiced without some or all of these specificdetails. In other instances, well known process steps have not beendescribed in detail in order to avoid unnecessarily obscuring thepresent invention. Other applications are possible, such that thefollowing examples should not be taken as limiting. In the followingdetailed description, references are made to the accompanying drawings,which form a part of the description and in which are shown, by way ofillustration, specific embodiments of the present invention. Althoughthese embodiments are described in sufficient detail to enable oneskilled in the art to practice the invention, it is understood thatthese examples are not limiting, such that other embodiments may beused, and changes may be made without departing from the spirit andscope of the invention.

For purposes of this disclosure, an information handling system mayinclude an instrumentality or aggregate of instrumentalities operable tocompute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, or other purposes. For example, an informationhandling system may be a personal computer, a network storage device, orany other suitable device, and may vary in size, shape, performance,functionality and price. The information handling system may includerandom access memory (“RAM”), one or more processing resources such as acentral processing unit (“CPU”) or hardware or software control logic,read only memory (“ROM”), and/or other types of nonvolatile memory.Additional components of the information handling system may include oneor more disk drives, one or more network ports for communicating withexternal devices, as well as various input and output (“I/O”) devices,such as a keyboard, a mouse, and a video display. The informationhandling system may also include one or more buses operable to transmitcommunications between the various hardware components.

The present invention relates in various embodiments to devices, systemsand methods involving information handling systems. In particularembodiments, the subject information handling devices, systems ormethods utilize data centers and associated components that are adaptedto multicast over VXLAN environments and systems. In addition, varioussoftware and firmware components can be included with the subject VXLANbased multicasting systems. A wide variety of software protocols,platforms and programs can be used, and it is specifically contemplatedthat any suitable protocol, platform or program can be used with thesystems and methods set forth herein. As specific non-limiting examples,Management and Provisioning Entity (“MPE”) software components such asthe VMControlCenter software system can be used, among otherpossibilities.

In various embodiments, one or more subject software infrastructures,programs or modules can provide for the specific reservation,distribution, adjustment and/or reassignment of interlink or fabricbandwidth, traffic or load. Such reservation, distribution, adjustmentand/or reassignment can be initially determined as may be appropriatefor start multicasting needs and parameters, and then adjusteddynamically as needs change over time. Various methods for determiningand managing such dynamic changes in load distribution over a VXLAN caninclude the use of congruent thresholds and utilization thresholds whilemonitoring overall traffic in order to create and restructure groups andtrees in real time, and thereby shift or otherwise alter load patternsand paths as needed.

In general, the disclosed VXLAN L3 multicast arrangements can be adaptedto maintain as few multicast forwarding entries (i.e., (*, G)) aspossible at the system core, while distributing the multicast trafficstreams evenly over the topology of the full network. This can avoidoverstressing or overreliance on some links while underutilizing others.This can be accomplished in part by dynamically using an MPE to assignOuterGroup addresses to the VTEPs, and by using a respective tenant toassign InnerGroup addresses to the VMs. In such arrangements, thetransport multicast encapsulation can then be (OuterGroup, InnerGroup).Monitoring traffic, establishing new trees or groupings, and changingmulticast groupings in real time as may be appropriate can then help tobalance loads. This can also involve spawning new trees when volumethresholds are reached. The creation and/or adjustment of such trees caninvolve the use of “phantom” Rendezvous Points (“RPs”) for existing andnewly created bidirectional (“BIDIR”) groups, with the RPs being chosenand placed in such a manner so as to stream multicast traffic throughdifferent parts of the network topology.

There can be several significant advantages to such a VXLAN arrangement.For one thing, the multicast states can be minimized in the networkcore, which allows for greater overall flexibility and speed in thenetwork. In addition, the dynamic establishment, distribution andadjustment of trees and groups results in utilizing many or all linksthrough the system in a more even and distributed manner, such thatparticular links or chains are not overloaded and localized trafficcongestion does not take place. Further, the techniques for assigningBIDIR trees to VTEPs can be the same or similar to that which is alreadyproposed for VXLAN, such that implementing the arrangements and methodsdisclosed herein is not overly burdensome.

Turning first to FIG. 1, an exemplary VXLAN topology is illustrated inblock diagram format. VXLAN 10 includes a pure IP core 20 at the networklayer (L3). Numerous interconnected network switches and routers 31-38coupled to the core 20 provide for a wide variety of possible multicasttrees that can route multicast traffic to various Top of Rack switches(“TORs”) 41-46. It will be readily appreciated that a plurality ofswitches/routers 31-38 can be configured as RPs for VXLAN 10. While only8 network switches/routers and 6 TORs are shown for purposes ofsimplicity, it will be readily appreciated that many multiples of eachof these types of switches can be present across a given VXLAN. Eachgiven TOR 41-46 can be coupled to a respective server or host 51-56,each of which can contain a VTEP 71-76 and one or more associated VMs 61a-66 c. Again, there can be many more servers and VTEPs than the severalshown, and each server can contain dozens, hundreds or more separateVMs, as will be readily appreciated. In various embodiments, one or moreservers 51-56 can be actual physical servers at the L2 level, which areall then interconnected at the L3 level over VXLAN 10. Various tenantscan be formed within or across servers 51-56, as will be readilyappreciated. In addition, an MPE 80 can be a software module orcomponent that is resident on a processor or other computing systemcoupled to the network, with the MPE being adapted to label and managegroup and tree formation.

Continuing with FIG. 2A, an exemplary VXLAN topology according to oneembodiment of the present invention is illustrated in block diagramformat. VXLAN 100 can be substantially similar to VXLAN 10, in that itincludes a pure IP core 120 at the network layer (L3), variousinterconnected network switches and routers 131-138 coupled to the core120 to provide for a wide variety of possible multicast trees that canroute multicast traffic, various hosts each having a VTEP 171-175 andassociated VMs, as well as an MPE 180 on an associated processor tolabel and manage group and tree formation. Similar to the foregoingexample, it will be readily appreciated that many more switches,routers, hosts, VTEPs, VMs and the like can be present in VXLAN 100, asrepresented by various unresolved links extending from routers 131, 136,138, and that the limited amount depicted are for purposes ofillustration only.

One notable feature of VXLAN 100 is that a plurality of routers can bepreconfigured as potential RPs, such as RPs 136 and 138. In fact, theoverall topology of VXLAN can be structured so that a full amount ofsuitable potential RPs 136, 138 are preconfigured and ready for use assuch. In one embodiment, the amount and distribution of preconfiguredpotential RPs can be designed with the maximum possible loads over theVXLAN in mind. As the VXLAN is used in practice though, not all of thepreconfigured potential RPs are actually used as such. Rather, the useof one or more of the preconfigured potential RPs can depend uponwhether such use is actually required for a given load. For example, inthe components depicted in FIG. 2A, light network traffic across theshown links might result in only router 136 being needed as an RP atthat time. In such case, router 138 would not act as an RP. In the eventof significantly increased loads though, then the overall system couldactivate the RP abilities of router 138 such that both of routers 136and 138 act as RPs. Deactivation of one or more RPs from that mode canthen also take place as traffic or loads decrease across the pertinentlinks.

A determination as to whether one or more preconfigured potential RPsthat are not currently acting as RPs should be activated as such candepend upon the dynamically changing traffic and loads across VXLAN 100.For example, a given BIDIR might have traffic across it increasesubstantially, such that it may be desirable to distribute the load forthis BIDIR. In such cases, some or all of the BIDIR can be split,reworked, or otherwise have various links and paths reassigned. This caninvolve the creation of new BIDIRs with newly designated RPs, which RPsare selected from inactive preconfigured potential RPs. Such changes cantake place as a result of a traffic threshold being reached across anygiven BIDIR.

Such a traffic threshold can be a “congruent threshold,” which canrepresent an amount of traffic beyond which is undesirable for a givenBIDIR. In some embodiments, the congruent threshold can relate to anamount of non-intersecting VTEPs among the various tenants under currentconsideration in a BIDIR. As one non-limiting particular example, for agiven congruent threshold of 90%, there might be permitted only 10% ofnon-intersecting VTEPs among a particular group of grouped BIFIR treesthat use the same OuterGroup multicast tree. One might also set anin-congruency threshold of 10%, indicating that the group of BIDIR treesgrouped together should have at least 90% of intersecting BIDIROuterGroup trees. Such a traffic threshold or “congruent threshold” canhave configurable values, which may be set as desired by a given VXLANdesigner or operator.

Moving next to FIG. 2B, an exemplary MPE according to one embodiment ofthe present invention is illustrated in block diagram format. MPE 180can be present within VXLAN 100 of FIG. 2A, and as such operates toassign, maintain, monitor traffic on and rearrange the various groupsand trees across the VXLAN. As such, MPE 180 can include specificmappings or tables for all of the currently designated and operatingBIDIR groups on VXLAN 100. For example, MPE 180 can have data regardingBIDIR 190 and BIDIR 191, which includes all VTEPs that are in eachrespective BIDIR and all VMs from each VTEP that are in that particularBIDIR. Although only two BIDIRs are shown, it will be readilyappreciated that many more can be present at a given time.

In addition to having data regarding all of the members of each activeBIDIR, MPE 180 can also have data on each BIDIR with respect to thepresent load across the BIDIR as well as the threshold value beforereassignment and redistribution of load will take place. Further, MPE180 can also contain data regarding all switches and routers throughoutthe VXLAN 100, as well as those that are preconfigured as potential RPs,as shown. In this manner, the MPE is able to select an appropriate RPwhen one or more new BIDIR groups are to be created due to increasednetwork traffic reaching a traffic threshold on a given BIDIR.

Although a wide variety of applications involving efficientlydistributing multicasting load across a VXLAN using the foregoingsystems can be envisioned, one basic method is provided here as anexample. Turning next to FIG. 3A, a flowchart of an exemplary method ofdistributing multicast load across a VXLAN is provided. In particular,such a method can involve efficiently using or operating an MPE or othersuitable computing module or system, in association with a VXLAN, suchthat VTEP groups, BIDIR trees and RPs are optimally created and alteredin response to multicast loads over the network. It will be readilyappreciated that not every method step set forth in this flowchart isalways necessary, and that further steps not set forth herein may alsobe included. For example, added steps to set or designate congruentand/or utilization thresholds can be included. Furthermore, the exactorder of steps may be altered as desired for various applications.

Beginning with a start step 300, a first process step 301 can involvepreconfiguring various routers as potential RPs across the VXLANtopology. This does not necessarily involve activating all of thepotential RPs as active RPs, but only configures them as such in theevent that they become needed as RPs at a later time. A subsequentprocess step 302 can involve a VMControlCenter module or other suitableMPE initially provisioning or establishing a single master BIDIR treefor a set of tenants with a specific RP. This can involve activating theRP from a potential to an active RP state. In various embodiments, theRP can be a “phantom” RP.

The various VTEPs over the network can then send Internet GroupManagement Protocol (“IGMP”) join requests to their respective TORs atthe next process step 304. At subsequent process step 306, the TORsintercept and inspect the sent IGMP join requests, after which the TORsforward information to the MPE regarding which associated VTEPs arejoining which BIDIR groups and for which tenants at process step 308. Aswill be readily appreciated, a single VTEP can be part of multipletenants, since they may instantiate VMs belonging to different tenants.

At subsequent process step 310, the MPE can then maintain or update adatabase that contains the mapping of VTEPs of a tenant to the masterBIDIR multicast group assigned. After this is done, the TORs can thensend respective Protocol Independent Multicast (“PIM”) join requests tothe specific RP assigned to the single master BIDIR tree at process step312, such that the multicast forwarding entry states (*,G) areinstantiated. Traffic can then flow through the transport network forthe established set of tenants through the provisioned master BIDIRgroup at process step 314. At decision step 316, an inquiry can then bemade as to whether further tenants need to be registered. If so, thensteps 302 through 316 are repeated for each new set of tenants, andadditional new BIDIR trees with specific RPs are provisioned for eachdifferent tenant set. For example, if there are 1000 tenants, thensubsets of 100 tenants each could be assigned to a given BIDIR tree andspecific RP. Of course, other amounts of tenants and divisions are alsopossible.

As all tenants are established with BIDIR groups and specific RPs,traffic is then monitored over the network by the various RPs at processstep 318. Traffic can be monitored at the various RPs, which again canbe phantom-like RPs, as well as at the various VTEPs by speciallyconfigured VM applications. The specially configured VM applications canutilize information that is naturally held by the VTEP, such as VM groupstatistics regarding how much local traffic is traveling on therespective inner VM groups. Specially configured VM applications tomonitor inner VM traffic within a VTEP can be placed based on thecongruence of inner VM group membership by the MPE. The VTEPs can thenupdate the MPE about the inner VM group traffic periodically at processstep 320.

While traffic is monitored, inquiries can be made as to whether athreshold has been reached at decision step 322. If no threshold hasbeen reached, then the method reverts to step 318. When a trafficthreshold has been reached, however, then the method continues toprocess step 324, where the affected RP notifies the MPE that theaffected link utilization has reached or crossed a given threshold. Sucha notification can be made by an out-of-band mechanism, such as aTransmission Control Protocol (“TCP”) connection, for example, from theRP to the MPE. Updates and/or notices from the VTEPs to the MPE can alsobe by way of the same or other out-of-band mechanisms. Other suitablecommunication techniques may also be used.

Upon receiving the threshold reached notification, the MPE then beginsto collate memberships of the VTEPs for all tenants in the affectedBIDIR group at process step 326. At process step 328, this can involvethe MPE finding the tenants having interested VTEPs that form anintersection amongst each other such that they fall within a “congruentthreshold.” Again, the congruent threshold can be a configurable value,and can represent the amount of non-intersecting VTEPs among the varioustenants under current consideration. At a subsequent process step 330,the MPE can then create a new BIDIR group with the tenants found in step328, as well as a new RP. This can involve activating a preconfiguredpotential RP from deactivated to an active state. The new RP ispreferably selected based upon existing network traffic, such that theactual new RP is less utilized than other potential new RPs. Uponcreating the new BIDIR group, the MPE can then send the new BIDIR groupinformation to affected VTEPs at process step 332.

Upon receipt of such information, the affected VTEPs can then send IGMPjoin requests to the TORs for their new BIDIR group at process step 334.The TORs then send PIM join requests to the new RP for the new BIDIRgroup at process step 336 and confirmation of these new IGMP joins isthen sent to the MPE at process step 338. New tenant traffic is thenflowed through the network for the new BIDIR group at process step 340.The affected VTEPs can then send IGMP leave requests to their old BIDIRgroup at process step 342, upon which the VTEPs are then removed fromsuch old groups. The old TORs report the leave requests to the MPE andthe MPE adjusts its VTEP membership tables to reflect the new membershipstatuses at process step 344.

The method then continues to a decision step 346, where an inquiry ismade as to whether the network is to continue to operate. If so, thenthe method reverts to process step 318, where traffic is monitored atthe RPs. If the network is to cease operation here, or at any time,however, then method proceeds to finish at end step 348.

Although the foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding, itwill be recognized that the above described invention may be embodied innumerous other specific variations and embodiments without departingfrom the spirit or essential characteristics of the invention. Variouschanges and modifications may be practiced, and it is understood thatthe invention is not to be limited by the foregoing details, but ratheris to be defined by the scope of the claims.

What is claimed is:
 1. A computing system comprising: a processoradapted to manage a plurality of routers, the plurality of routers beingcoupled to a plurality of servers, wherein each of said routers isadapted to facilitate network data communication among the plurality ofservers according to multicast trees; and one or more modules adapted tobe executed with respect to said processor, said one or more modulesbeing configured to: dynamically select one or more active rendezvouspoints (“RPs”) for the multicast trees from among the routers that arepotential RPs for the multicast trees so as to balance loads associatedwith the network data communication; and receive information on trafficpassing through the one or more active RPs.
 2. The computing system ofclaim 1, wherein the one or more modules are adapted to facilitate therearrangement of an existing multicast tree.
 3. The computing system ofclaim 2, wherein the one or more modules are adapted to facilitate therearrangement of the existing multicast tree based upon a volumethreshold of traffic in the existing multicast tree.
 4. The computingsystem of claim 1, wherein the one or more modules are adapted toreceive a notification when a volume threshold of traffic is reached inone of the active RPs.
 5. The computing system of claim 1, wherein eachof said potential RPs do not act as RPs unless the one or more moduleshave designated them as an RP.
 6. The computing system of claim 1,wherein said traffic passing through said one or more active RPscomprises multicasting traffic.
 7. The computing system of claim 1,wherein each server includes a VXLAN tunnel end point (“VTEP”) and aplurality of virtual machines (“VMs”) thereupon.
 8. The computing systemof claim 7, wherein the multicast trees are configured as bidirectionalgroups (“BIDIRs”) having designated VMs thereupon.
 9. An informationhandling system comprising: a plurality of servers; and a plurality ofrouters coupled to said servers, each router being adapted to facilitatenetwork data communication among the plurality of servers according tomulticast trees, wherein more than one of said plurality of routers areconfigured as potential rendezvous points (“RPs”) for the multicasttrees; wherein one or more active RPs are dynamically selected from thepotential RPs to balance loads in the information handling system. 10.The information handling system of claim 9, wherein existing multicasttrees are rearranged based upon a volume threshold of traffic beingreached in the existing multicast trees.
 11. The information handlingsystem of claim 9, wherein existing multicast trees are rearranged bycreating a new multicast tree and moving traffic from the one of theexisting multicast trees to the new multicast tree.
 12. The informationhandling system of claim 9, wherein the active RPs send notices when avolume threshold of traffic is reached through the active RPs.
 13. Theinformation handling system of claim 9, wherein a module containsinformation regarding which routers are configured as the potential RPs.14. The information handling system of claim 9, wherein traffic passingthrough said plurality of routers comprises multicasting traffic. 15.The information handling system of claim 9, wherein each of said morethan one routers that are configured as potential RPs do not act as RPsunless one or more modules have designated them as an RP.
 16. Theinformation handling system of claim 9, wherein each server includes aVXLAN tunnel end point (“VTEP”) and a plurality of virtual machines(“VMs”) thereupon, and wherein the multicast trees are configured asbidirectional groups (“BIDIRs”) having designated VMs thereupon.
 17. Amethod of distributing a multicasting load across a network, the methodcomprising: preconfiguring a plurality of routers as potentialrendezvous points (“RPs”); establishing one or more multicast treeshaving designated activated RPs; monitoring network traffic at theactivated RPs; determining that a traffic threshold has been reached ata first activated RP within a given multicast tree; and removing one ormore tenants from the given multicast tree and placing said one or moretenants into a different multicast tree.
 18. The method of claim 17,wherein the different multicast tree is a newly established multicasttree in response to the determination that the traffic threshold hasbeen reached.
 19. The method of claim 17, further comprising receiving amessage from the first activated RP that the traffic threshold has beenreached.